Energy efficiency is a key factor in designing refrigeration systems. However, at the same time, the increased cost of manufacturing more energy efficient refrigeration systems must be considered. Conventional refrigerator appliances commonly utilize a single evaporator, fan, and damper to move cooled air from the frozen food compartment containing the evaporator to the fresh food compartment. The position of the damper can be controlled depending upon whether cooling of the fresh food compartment is needed. One or more temperature sensors are utilized to measure temperature in one or more of the compartments.
Refrigeration systems that use dual evaporators rather than a single evaporator can be useful for removing heat from two different locations in a more energy efficient manner than single evaporator systems. For example, in a refrigerator appliance, a refrigeration loop can be provided that uses one evaporator to remove heat from the fresh food compartment and another evaporator to remove heat from the frozen food compartment. Such dual evaporator systems can be useful in e.g., avoiding temperature and/or humidity gradients that can occur with single evaporator systems.
Dual evaporator refrigeration systems can be costly and more complex than single evaporator refrigeration systems, where the increased cost of manufacturing can outweigh improvements in energy efficiency. Dual evaporator refrigeration systems can also incur cycling losses when switching operation from the fresh food evaporator to the freezer evaporator. Evaporators in such existing systems are also known to be relatively large, which can impact the storage volume of the appliance in which the refrigeration system resides. Some dual evaporator systems also utilize dual compressors, which further increases cost, noise and reliability concerns.
As such, dual evaporator refrigeration systems have been developed that provide for improved efficiency in operation and reduced complexity. Such refrigeration systems can cool multiple locations to different temperatures simultaneously. Nevertheless, there is room for improvement in the efficiency of these refrigeration systems. In this regard, a refrigerant that can provide for improved efficiency in the operation of dual evaporator refrigeration systems that cool multiple locations to different temperatures simultaneously without having to change the design of such a refrigeration system would also be useful.